Why Does My Hair Grow So Slow?

Written by Our Editorial Team

Last updated Mar 12, 2023

While hair loss and androgenetic alopecia are alarming conditions, why does my hair grow so slow is also a common complaint. The normal rate of hair growth is approximately 0.5 inches per month, however, this varies greatly among different individuals.

The majority of the causes of slower hair growth are reversible such as dietary habits and different types of stressors. Subsequent sections will educate the readers on the causes and treatments of slower hair growth.

Read more:

What is a hair growth cycle?

hair follicle growth cycle close-up model

Before discussing the reasons underlying slow hair growth, it is imperative to have background knowledge regarding the normal and natural hair growth cycle. Following are the three key phases of the healthy hair growth cycle.

Anagen Phase

Anagen or growth phase of the hair growth cycle is characterized by the rapid proliferation of melanocytes as well as hair follicular cells. Melanocytes produce an increased concentration of melanin pigment during this stage of the hair cycle. Rapid activation and division of hair follicular cells cause the hair shaft to grow longer and the extracellular matrix components to increase in concentration.

The anagen phase lasts for approximately two to six years, depending on the location of hair growth. The duration of this phase is proportional to the length of the hair shaft, therefore, relatively longer scalp hair has a relatively longer anagen phase. At any given time, approximately 85-90% of the total hair resides in the anagen phase of the normal hair growth cycle.

Catagen Phase

The phase is also referred to as the transitional or follicular regression stage of the hair growth cycle. During this phase, melanocytes terminate the synthesis of melanin pigment and the proliferation of hair follicular cells also stop. Moreover, the hair follicles regress towards the superficial surface of the scalp.

This transitional phase lasts for only two to three weeks after which the hair follicles enter the final stage of the hair growth cycle, the telogen phase. The characteristic feature of the catagen phase is the formation of club hair. This hair has a club-like structure at the hair roots formed as the root bulb shrinks. This represents the keratin proteins that are responsible for the formation of the hair strand.

Telogen Phase

The phase is also known as the resting phase of the hair growth cycle. The term 'resting phase' implies that the hair follicles remain dormant during this stage accompanied by complete cessation of hair growth. However, the hair strands remain loosely attached to the hair follicles during this stage.

Scalp hair remains in the telogen for almost a year unit they enter the exogen phase, an extension of the telogen phase characterized by the liberation of hair strands from the hair follicles. Approximately 10-15% of the total body hair is present in the telogen phase at a given time. Hair shedding may occur during this stage, assisted by activities such as brushing or washing hair. Soon, hair follicles enter the next hair growth cycle.

How fast does hair grow normally?

According to the American Academy of Dermatology, the average rate of growth of hair is half an inch per month or approximately six inches per annum.

However, the provided rate of hair growth is not definitive and may vary among individuals of different ages, sex, race, ethnicity, and genetic makeup i.e. Asian hair type grow and baby hair type. Several environmental, psychological, physiological, and pathological factors also influence the rate of hair growth.

Your hair texture, however, does not affect your growth rate. Curly hair does not grow any faster than other hair textures.

Why does your hair grow so slow?

A reduced hair growth rate can be alarming for many individuals. The decline in the rate of hair growth is a manifestation of the interplay of numerous etiological factors. Surprisingly, some of these factors are potentially reversible owing to improved dietary and lifestyle habits. The following factors contribute to a reduced rate of hair growth.

Genetic Predisposition

Genetic predisposition in combination with hostile environmental factors contributes to a reduced rate of hair growth. Research studies suggest that up to six thousand genes are involved in the hair morphogenesis and progression of the hair growth cycle. The gene expression follows a circadian clock mechanism correlating with the hair growth cycle.

Gene expression is recorded at its peak during the transition between telogen and anagen phases of the hair cycle. These genes are also involved in the DNA repair mechanisms and modulated the accumulation of reactive oxygen species in the hair follicles. Genetic abnormalities disrupt the hair growth cycle and affect the longevity of the hair follicular cells.

These genes can also dictate where your hair grows - which might lead to some unwanted hair.

Dietary Deficiency

An adequate supply of nutrients is not only important for the normal proliferation of hair follicular cells and progression of the hair growth cycle but is also important for maintaining the overall wellbeing of the body. Psychological, endocrine, and physical health are the key determinants of the overall health of hair.

Protein malnutrition, caloric restriction, iron, zinc, niacin deficiencies, and depletion of other macronutrients and micronutrients from the body elicit hair loss. Iron is important for normal DNA synthesis and hair follicle proliferation. Iron is also known for regulating gene expression concerned with hair growth.

Zinc is an important component of the Hedgehog signaling pathway involved in hair follicle morphogenesis. Therefore zinc deficiency may lead to hair loss and reduced hair growth. The deficiency of essential fatty acids also leads to a reduced rate of hair growth. These fatty acids mimic finasteride as they inhibit 5-alpha reductase and modulate the action of androgens on the hair follicles.

Selenium deficiency also manifests as a reduced rate of hair growth. Despite being a trace element in the human body, selenium protects the hair follicles against oxidative damage as well as modular hair follicle morphogenesis.

Vitamin D deficiency is known for its musculoskeletal consequences. However, this may also have negative effects on hair health. Hair loss conditions such as telogen effluvium and female pattern hair loss may be exacerbated in the presence of vitamin D deficiency.

Since biotin or vitamin B7 increases protein synthesis and DNA replication, its deficiency is also associated with alopecia and decreased rate of hair growth.

Vitamin A and Vitamin E also play a role in assisting hair growth.

Stress

Humans are constantly exposed to environmental, psychological, social, and internal stressors. These stressors significantly influence the progression of hair follicles through the hair growth cycle. Stress induces apoptosis of hair follicle cells as well as suppresses the proliferation of keratinocytes.

Stress also causes the hair follicles to prematurely exit the anagen phase and enter the catagen and telogen phases of the hair cycle. It also stimulates perifollicular infiltration of inflammatory cells that further promote suppression of the hair follicles.

Scalp Conditions

Scalp health and hair growth are interrelated with each other. Dermatologic scalp pathologies play a significant role in the onset of hair loss conditions and reduced rate of growth of scalp hair. These pathologies include dandruff, atopic dermatitis, seborrheic dermatitis, psoriasis, and scalp aging. These scalp conditions pose oxidative stress to the hair follicles and may have severe consequences on the growth and overall health of hair.

Chemicals and Hair Damage

shampooing because of slow hair growth from chemicals

Harmful chemicals present in dyes and other hair products are detrimental to existing hair and may also affect the growth of new hair. These chemicals are metabolized and result in the production of free radicals and reactive oxygen species. These substances cause oxidative damage to different cellular entities including hair follicles.

Reactive oxygen species cause damage to DNA in keratinocytes. Oxidant creams commonly used in hair dyeing have relatively higher oxidative activity.

Endocrine Abnormalities

Hormonal imbalances play a key role in the disruption of the hair growth cycle and may cause a decline in the rate of hair growth. Hormones involved include androgens, estrogen, progesterone, and prolactin. Hair follicles are also greatly influenced by thyroid gland hormones, melatonin, cortisol, and corticotropin-releasing hormone.

Disruption in the hormone levels may hurt hair growth. Hormone disruption during pregnancy and menopause is also responsible for eliciting hair loss and hindering hair growth.

Relevant reads:

How to grow hair faster medicinally?

There are several options you can consider to have your desired hair length:

Minoxidil and finasteride are two pharmacologic formulations that are approved by the US Food and Drug Administration for the treatment of hair loss and reduced hair growth.

Finasteride suppresses the activity of 5-alpha reductase and prevents the androgens from disrupting the hair growth cycle. Minoxidil, on the other hand, stimulates potassium channels that in turn promote the proliferation of hair follicle cells.

How to grow your hair faster at home?

To turn your short hair into the length you want at home, here are things you can try:

Scalp Massage

Scalp massage is one of the widely used conventional techniques to boost hair growth. Scalp massage stimulates blood to flow towards the scalp as well as modulates stress. This promotes hair growth both directly and indirectly by reducing stress levels and regulating the levels of stress hormones such as cortisol.

Supplements

Dietary supplementationalso plays a crucial role in the treatment and management of reduced hair growth. As mentioned in the preceding discussion, both micronutrients and macronutrients play an important role in promoting normal hair growth. Therefore, it is imperative to consume a healthy and well-balanced diet along with effective management of stress.

Learn more about the supplement for your hair.

Hair Extensions

Hair extensions have been used to simulate a variety of different hairstyles and colors. In some communities, hair extensions are used extensively to change up your hair color while not dyeing your natural hair thus protecting them from damage that can cause brittle hair and hair fall.

For example, you can use hair extensions to get black hair, curly hair, and even long hair.

Hair Care Products

Choosing appropriate hair care products is important to first give your hair the nourishment it needs, and also to help combat hair thinning, hair breakage, and female and male pattern hair loss.

Scandinavian Biolabs and our scientists have thoroughly tested and formulated a trademarked Bio-Pilixin® concoction that will be your best friend against hair loss, thinning hair, and slow hair growth.

In fact, our values are rooted in transparency and effectiveness that we offer a 150 days guarantee (almost 5 months!) that our products will work for you. If it doesn't, you'll get all your money back with no complicated process.

Learn more about our products for men and women.

Essential Oils

Essential oils, while with very limited scientific backings, have been shown to work for many. The main benefits of this treatment are that it's widely available and cheap to use. However, when it comes to hair care, it's recommended to opt for products with reliable scientific research and effectiveness studies.

Read our collection on essential oils:

Conclusion

Slower hair growth is one of the common hair-related complaints among people from different age groups.

Internal factors responsible for causing reduced hair growth include hormonal imbalances, psychological stress, and genetic susceptibility. External or environmental factors include nutrient deficiencies, environmental stress, unhealthy scalp, and chemical-induced damage to hair follicles.

A variety of pharmacologic and herbal treatments are available for elevating hair growth in conjunction with the modification of dietary and lifestyle habits.

Not satisfied? Check out our hair growth guides: